Many aspects of modern society require the communication of data pursuant to the effectuation of communication services. And, the need to communicate data shall likely continue and perhaps increase as advancements in communication technologies permit additional types of communication services to be effectuated.
Data is communicated by way of a communication system. A communication system includes, at a minimum, a set of communication stations including a first communication station and a second communication station. The communication stations are interconnected by way of a communication channel. Data is originated at a first of the communication stations, referred to as a sending station. The data is sent by the sending station upon the communication channel to be delivered to at least a second of the communication stations, referred to as a receiving station. The receiving station detects the data communicated thereto and operates to recover the informational content thereof.
A radio communication system is a communication system that utilizes radio channels upon which to communicate data between the communication stations. The radio channels are formed upon radio links defined upon a radio air interface. Wire line communication systems, in contrast, require a fixed, i.e., a wire line, connection between the communication stations upon which to form communication channels that are permitting of the communication of data therebetween.
Radio communication systems provide various advantages that sometimes favor their use over corresponding wire line communication systems. The physical infrastructure of a radio communication system, for instance, is generally relatively less costly to install than that of a corresponding wire line communication system. Initial deployment costs of a radio communication system, therefore, are generally less than those of corresponding wireline communication systems. Additionally, and significantly, a radio communication system can be implemented as a mobile communication system. In a mobile communication system, communication mobility is provided. That is, one or more of the communication stations of a mobile communication system is mobile and not limited to operation at a fixed position.
A cellular communication system is a type of mobile radio communication system that has achieved significant levels of usage. The networks of various cellular communication systems have been deployed to encompass many populated portions of the world. Telephonic communications are provided by way of the networks of cellular communication systems through the use of mobile stations. That is, radio communications are effectuated during operation of the cellular communication system between a network part of the communication system and a mobile station to effectuate a communication service.
The area encompassed by the cellular communication system is defined by the placement of fixed-site base transceiver stations. The base transceiver stations each define a coverage area, referred to as a cell, and the aggregated areas of the cells defined by the coverage areas of all of the base transceiver stations together define the area encompassed by the system. The network part of the cellular communication system also includes control entities and entities permitting connection with other communication networks, such as PSTNs (public-switched, telephonic networks) or PDNs (packet data networks), such as the Internet.
A mobile station, when used to communicate data, usually communicates with the base transceiver station positioned in closest proximity to the mobile station. Viz., the mobile station communicates with the base transceiver station that defines the cell in which the mobile station is positioned.
Successive generations of cellular communication systems have been developed and deployed. New-generation systems are being deployed and others are under development. Certain of the new-generation systems are referred to as being third-generation (3G) systems. In general, these systems are predicated at least in part upon packet-based communication schemes. In a packet communication scheme, data that is to be communicated is formatted into packets and the packet-formatted data is communicated in the form of a series of data packets to effectuate the communication of the data pursuant to a communication service. And, additional systems, sometimes referred to as successor-generation systems, are also predicated at least in part upon packet-based, e.g., frame-formatted, communication schemes.
The operating parameters are of an exemplary third generation communication system is set forth in an operating specification referred to as the CDMA 2000 operating specification. The operating parameters set forth in the CDMA 2000 operating specification provides for packet based data communication services. Further operating parameters related to high speed data communication services have also been promulgated to provide for the effectuation of high speed data communication services in the CDMA 2000 system. A 1×EV-DV data communication scheme, for example, provides the operating parameters pursuant to which high speed data communication services can be effectuated in conjunction with a CDMA 2000 communication system. High speed data communication services are effectuated in either direction, i.e., by the network part to a mobile station as well as, also, by a mobile station to the network part.
Existing versions of the operating specification define the communication system in terms of logical layers, including an RLP (Radio Link Protocol) logical layer and an MAC (Medium Access Control) layer or sub-layer. RLP-formatted data packets, or frames, are formed at the RLP layer, and MAC layer formatting is performed at the MAC layer. Both layers utilize a feedback acknowledgment scheme used to determine whether to retransmit a data frame. The RLP layer utilizes a NAK-based retransmission scheme and the MAC layer utilizes and H-ARQ scheme.
Additionally, the operating specification defines a reverse Packet Data channel (R-PDCH). Two different types of transmissions are permitted on this channel. First, autonomous transmission is defined. In autonomous transmission, an “always on” data connection, minimally controlled, is provided. When the mobile station operates pursuant to autonomous transmission, the mobile station is permitted to communicate data at a data rate up to a predetermined data rate. Scheduled transmission is also defined. In scheduled transmission, the network part, e.g., the base station, determines when the mobile station is permitted to transmit at next higher rates from the autonomous transmission, up to the peak data rate. In addition to the communication of relatively short frame lengths, e.g., five or ten milliseconds, to improve the delay performance of communications, hybrid ARQ (H-ARQ) feedback is also utilized for the reverse link to reduce the frame error rate due to power control inaccuracies.
For instance, any time in which the mobile station is to communicate data, the mobile station is autonomously permitted to transmit at data rates up to a data rate, e.g., 9.6 kbps, specified during the call set-up procedures. For scheduled transmission, the mobile station requests permission to transmit, and the network part responds with a grant, including a rate assignment. The mobile station is then permitted to transmit the data during a permitted duration and at a permitted data rate.
Both autonomous and scheduled transmission uses the same type of H-ARQ feedback acknowledgment mechanism. The H-ARQ scheme exhibits the attributes of multiple ARQ “channels” and synchronous acknowledgment. Retransmissions of an encoder packet is performed up to a selected number of retransmissions. With the use of reverse link H-ARQ procedures, a symmetric H-ARQ mechanism is provided at the MAC sub-layer between the mobile station and the base transceiver station of the communication system.
One problem with the existing communication scheme set forth in the existing version of the operating specification pertains to feedback acknowledgments during retransmission of data packets or frames. An RLP-formatted frame might first be communicated in non-segmented form at a high data rate and then retransmitted in segmented form at a lower data rate. When retransmitted at the lower data rate, a base transceiver station forming a receiving station might indicate a failure of delivery of the data due to timeout caused by its retransmission at a low data rate even through the retransmission of the data frame is ongoing.
Additionally, due to the multiple layers of feedback acknowledgments, excessive air resources are used to communicate the feedback acknowledgments at the multiple layers. The multiple-layer feedback is duplicative and wasteful of radio resources.
If a manner could be provided by which better to provide control over the retransmission of data pursuant to an acknowledgment feedback scheme would therefore be advantageous.
It is in light of this background information related to retransmission of data in a packet communication system that the significant improvements of the present invention have evolved.